Automated Optical Inspection(AOI) for PCB
What Is An Automatic Optical Inspection?
Automated Optical Inspection is a device based on optical principles to detect common defects encountered in soldering production. AOI is a newly emerging new testing technology that is developing very rapidly. The Venture has introduced high-end AOI testing equipment from home and abroad. When performing an automatic inspection, we scan the PCB automatically by the camera on the AOI machine, and the image is collected. We compare the tested solder joints with the qualified parameters in the database. After the image processing, the AOI will check the defects on the PCB and pass the display or automatic marking to display/mark the flaws so that our maintenance personnel can repair them.
Why Did Venture Introduce AOI Equipment?
In the early days, technicians mostly used AOI automatic optical inspection equipment to detect defects in the surface printing of IC (integrated circuit) packaging. With the evolution of technology, we used the AOI in the SMT assembly line to detect the quality of the parts on the circuit board. After the solder assembly or check whether the solder paste printing meets the standards.
The most significant advantage of AOI automatic optical inspection equipment is replacing the previous SMT pre-furnace, post-furnace manual visual inspection operations. It can also be more accurate than the human eye to determine the shortcomings of SMT assembly of the beaten parts. But just like manual inspection, AOI can only check the object’s surface correctly. But for, the solder joints hidden under the components or the edge of the parts may be limited. Of course, many AOI can now be made for multi-angle photography to increase its ability to detect the IC foot warp. And improve the camera angle of specific masked components. Obscured components of the camera angle to provide a more detection rate.
The Main Features Of AOI Technology
- High-speed detection system.
- It has a fast and convenient programming system.
- Use rich, unique multi-functional detection algorithms and binary or gray-level optical imaging processing technology to detect.
- According to the instantaneous change of the position of the detected component, the detection window will be automatically corrected to achieve accurate detection.
- Using ink directly marked on the PCB board or on the operation display with graphical error to check the electrical detection.
The Two Main Objectives Of The Implementation Of AOI
- The Final Quality
Monitoring the final state of the product as it goes down the line. This objective is preferred when production problems are apparent, the product mix is high, and quantity and speed are critical factors. Technicians typically place AOI at the far end of the line. The equipment can produce a wide range of process control information at this location. - Process Tracking
Venture uses inspection equipment to monitor the production process. We can obtain detailed data on defect classification and component placement offset. We prioritize this goal when product reliability is essential, high volume manufacturing with a low mix, and stable component supply. That often requires the placement of inspection equipment at several locations on the production line to monitor specific production conditions in-line. And provide the necessary basis for production process adjustments.
Let Venture’s Engineers Tell You Where You Should Place The AOI For Inspection
As a PCB manufacturer with more than ten years of experience, our excellent engineers have come to some conclusions about AOI placement. Although many can use AOI in multiple positions on the production line and each function can detect particular defects. But you can place automated optical inspection equipment where it can identify and correct the most flaws. There are three inspection locations that our engineers consider to be primary.
* After Solder Paste Printing
If the solder paste printing process meets the requirements, then the number of defects found by ICT can be reduced significantly. Typical printing defects include the following:
- Insufficient solder on the pads.
- Too much solder on the pad.
- Poor solder-to-pad overlap.
- Solder bridges between pads.
On ICT, Minor under-soldering rarely results in defects, while severe conditions, such as radical tinlessness, almost always result in defects at ICT. Insufficient solder may cause component loss or open solder joints. Nevertheless, deciding where to place an AOI requires recognition that component loss may occur for other reasons that you must place within the inspection plan. Inspection at this location most directly supports process tracking and characterization. Quantitative process control data at this stage include print offset and solder volume information. While qualitative information regarding printed solder is also generated.
Pre-Reflow
This location is ideal for placing inspection machines, as technicians can find most defects in solder paste printing and machine placement. Quantitative process control information is generated to offer calibrating information for high-speed wafer machines and tightly spaced component mounting equipment. Technicians use this information to modify component placement or indicate that they need to calibrate the laminator. The inspection of this position enables technicians to track the target process.
Post Reflow
Inspection at the final step of the SMT process is the most popular choice for AOI, as this location can detect all assembly errors. Post reflow inspection provides a high level of security as it identifies errors caused by the solder paste printing, component placement, and reflow processes.
Venture solves production problems efficiently with this technology, achieving fast turnaround times and high-quality product delivery. Working with Venture will be a good choice for you.
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